21428750 has 80 divisors (see below), whose sum is σ = 47984640. Its totient is φ = 7020000.

The previous prime is 21428747. The next prime is 21428791. The reversal of 21428750 is 5782412.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 271211 + ... + 271289.

It is an arithmetic number, because the mean of its divisors is an integer number (599808).

Almost surely, 2^21428750 is an apocalyptic number.

21428750 is an abundant number, since it is smaller than the sum of its proper divisors (26555890).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21428750 is an equidigital number, since it uses as much as digits as its factorization.

21428750 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21428750 is about 4629.1197867413. The cubic root of 21428750 is about 277.7573836879.

The spelling of 21428750 in words is "twenty-one million, four hundred twenty-eight thousand, seven hundred fifty".